In the related art, techniques for detecting eyeball information on the eyeballs of an occupant, such as a pupil position of the occupant, based on a captured image obtained by imaging a face of the occupant of a vehicle with an imaging device, have been studied.
In general, in the captured image, the eyes appear as red eyes or appear in other forms in accordance with the condition of light. Here, JP 2009-254691A (Reference 1) discloses a method for detecting eyeball information regardless of variation in how the eyes appear in the captured image, using two types of illumination including illumination for emitting light toward the face (eyes) of an occupant from a direction the same as an imaging direction and illumination for emitting light toward the face (eyes) of the occupant from a direction different from the imaging direction, based on a difference between two types of captured images including a captured image acquired when the light is emitted by the former illumination and a captured image acquired when the light is emitted by the latter illumination.
However, in the related art described above, in order to emit the light from different directions to the same position, it is necessary to dispose the two types of illumination at positions separated from each other to some extent, and thus, the degree of freedom in design and layout of a vehicle interior deteriorates while detection accuracy of eyeball information is ensured.
Thus, a need exists for an eyeball information detection device, an eyeball information detection method, and an occupant monitoring device which are not susceptible to the drawback mentioned above.